Abbott RealTime HCV Assay Research Articles

Performance of HCV core antigen and PCR testing in a predominantly genotype 3 population.

Hepatitis C core antigen (HCVcAg) is becoming increasingly recognized as an alternative to molecular testing for the confirmation of chronic hepatitis C. However, there are limited data on the performance of this assay in a genotype 3 (GT3) predominant country like Pakistan. We conducted a study to evaluate the diagnostic performance of HCVcAg against the HCV polymerase chain reaction (PCR) molecular test. HCV antibody-positive patients requiring confirmatory testing were recruited from August to October 2018 at the Pakistan Kidney and Liver Institute and Research Center (PKLI&RC), Lahore, Pakistan. Patients with previously known diagnoses or treatment histories were excluded. The Abbott HCV Ag assay was used for HCVcAg testing. Results ≥3.00 fmol/L were considered positive for HCVcAg. The Abbott RealTime HCV assay was used for PCR testing with a lower detection limit of ≥12 IU/mL. We computed the sensitivity, specificity and correlation of HCVcAg against HCV PCR. A total of 394 patients were recruited. The median age of the patients was 42 years. Most participants were females (51.5%, n = 203), 30.7% (n = 121) had HTN, 10.4% DM (n = 41) and 5% had APRI ≥2. The overall sensitivity was 98.0% and the specificity was 98.6%. The lowest detection limit of cAg was an HCV RNA value of 4657 IU/mL. The levels of cAg were highly correlated with those of HCV RNA by Spearman's rank correlation test (r = 0.935, p < .001). HCVcAg represents a suitable alternative with high sensitivity and specificity compared with HCV PCR in the GT3-predominant population and can be incorporated into algorithms to improve linkage to care.

Evaluation of the Point of Care Molecular Diagnostic Genedrive HCV ID Kit for the detection of HCV RNA in clinical samples.

2. Abstract BACKGROUND Despite the availability of an effective treatment for HCV infection, major bottle neck in the HCV care cascade is difficulty in getting the HCV RNA done on serologically positive (antibody to HCV) patients. This is due to the limited availability of HCV RNA test in the periphery. Nucleic acid amplification testing at point of care might revolutionise the HCV care continuum through its increased sensitivity, decreased turn around time and ease of performance in the field. Genedrive is one such assay which has recently got a CE- IVD certification. OBJECTIVES The diagnostic accuracy of Genedrive HCV ID kit for the qualitative detection of HCV RNA was evaluated by comparing with Abbott HCV RNA in an Indian demographic setting and across a range of different genotypes commonly found in India. STUDY DESIGN For the assay evaluation 150 HCV RNA positive and 170 HCV RNA negative samples as tested by Abbott HCV RNA assay (Abbott, Wiesbaden, Germany) on Automated m2000sp/m2000rt platform, as per the manufacturer’s instructions, that were retrieved from −80°C in the Virology repository were included in the study. All the samples were retrieved and re tested for HCV RNA on Genedrive HCV ID kit and compared with Abbott HCV RNA results. RESULTS Comparison of the Genedrive HCV ID kit with the Abbott Real Time HCV assay revealed a sensitivity of 100 % (95% CI 97.9 to 100) and a specificity of 100 % (95% CI 97.9 to 100) with a positive predictive value and negative predictive value of 100%. Overall diagnostic accuracy of Genedrive was found to be 100% (95% CI 98.9 to 100). CONCLUSION This study demonstrates that Genedrive HCV ID kit can be used for decentralised testing of HCV and ultimately finding the missing million. Highlights Decentralisation of HCV RNA assays is the need of hour for finding the missing millions. Genedrive HCV ID kit is one such assay which can qualitatively detect HCV RNA and can be used as a point of care molecular assay thereby reducing the dropouts and improving the HCV care cascade.

Clinical utility of hepatitis C virus core antigen assay in the monitoring of direct-acting antivirals for chronic hepatitis C.

BackgroundHepatitis C virus core antigen (HCV Ag) assay has been proposed as a more economical alternative to HCV RNA detection. This study aimed to investigate the clinical utility of HCV Ag assay in the monitoring of direct-acting antivirals (DAAs) for chronic hepatitis C patients.MethodsWe analyzed serum samples from 110 patients treated with paritaprevir/ritonavir, ombitasvir, and dasabuvir (PrOD) with or without ribavirin. The levels for both HCV Ag and HCV RNA assessed by COBAS TaqMan HCV (CTM) Test or Abbott RealTime HCV (ART) assay were evaluated at baseline, week 2, 4, and 12 during treatment and 12 weeks after completion.ResultsBaseline HCV Ag levels showed good correlations with HCV viral load (r = 0.879; p<0.001); whereas the correlation was slightly stronger with CTM test than with ART assay (p = 0.074). The concordance of HCV Ag and HCV RNA undetectability was significantly better in CTM test than in ART assay at week 2 (p = 0.003) and week 4 (p = 0.003). A sustained viral response 12 weeks off therapy (SVR12) was achieved in 108 patients (98%); the HCV Ag assay identified 99% of these patients. Both undetectability of serum HCV Ag and HCV RNA had high positive predictive value at week 2 (98% vs. 100%) and at week 4 (97% vs. 99%) in predicting SVR12.ConclusionsHCV Ag assay may be a feasible alternative to HCV RNA for the determination of SVR12 in patients treated with DAAs.

Significance of detectable HCV RNA below the limit of quantification in patients treated with DAAs using standard and ultrasensitive protocols

Predictive factors of HCV relapse after treatment with DAAs are poorly understood. In this study, we aimed to assess whether the residual viral load positivity observed during or at the end of treatment (EOT) has an impact on viral outcome. Blood samples were collected from 337 patients with genotypes (GT) 1a, 1b, 2, 3, and 4 HCV chronic infection, treated with DAAs to determine HCV RNA load by the Abbott RealTime HCV (ART) assay at treatment week (W) 4, at EOT, and 4, 12, 24 weeks after discontinuation. EOT and other samples with "detected <12/mL" (DNQ) were retested by an ultrasensitive protocol (USP) to confirm the result. Frequency of DNQ was analyzed in subgroups of patients and clinical conditions to assess potential correlations. At W4, 22% and 30.9% of the samples were undetectable and DNQ by ART assay, respectively, but no correlation for achieving SVR was found. In contrast, an HCV RNA cut-off of ≥50/mL at W4 was a significant predictor of therapy failure (P = 0.036, univariate analysis). At EOT, DNQ was associated to 12W treatment duration (P < 0.001) and GT1a infection (P = 0.036). Overall, 20/41 (48.8%) of DNQ samples at EOT or post-treatment W4, were confirmed by USP but only in a single case the patient experienced viral relapse. HCV RNA at W4 can predict SVR, irrespective to genotype or DAA regimen. HCV RNA DNQ at EOT is associated to shorter treatment duration and to GT1a, but is not a predictor of therapy failure.

Implications of HCV RNA level at week 4 of direct antiviral treatments for hepatitis C.

We aimed to determine whether the HCV viral load after four weeks of treatment (W4VL) with direct-acting antiviral agents (DAAs) predicts sustained virologic response (SVR) in a real-world clinical setting. We identified 21095 patients who initiated DAA-based antiviral treatment in the national Veterans Affairs (VA) healthcare system from 01/01/2014 to 06/30/2015. Week 4 viral load was categorized as undetectable, detectable below quantification (DBQ), detectable above quantification (DAQ) with viral load ≤42IU/mL and DAQ with viral load >42IU/mL. Week 4 viral load was undetectable in 36.1%, detectable below quantification in 45.6%, DAQ ≤42 in 9.3%, DAQ >42 in 9.1%. Detectable above quantification was much more common and undetectable week 4 viral load much less common when tested with the Abbott RealTime HCV assay vs the Roche COBAS AmpliPrep/COBAS TaqMan Version 2 assay. Compared to patients with undetectable week 4 viral load (SVR=93.5%), those with detectable below quantification (SVR=91.8%, adjusted odds ratio [AOR] 0.79, P-value=.001), DAQ ≤42 (SVR=90.0%, AOR 0.63, P-value<.001) and DAQ >42 (SVR=86.2%, AOR 0.52, P-value<.001) had progressively lower likelihood of achieving SVR after adjusting for baseline characteristics and treatment duration. Among genotype 1-infected patients who were potentially eligible for 8-week sofosbuvir/ledipasvir monotherapy, we did not find evidence that treatment for 12weeks instead of 8weeks was associated with higher SVR, even among those with detectable above quantification. In summary, DBQ and DAQ W4VL are very common in real-world practice, contrary to what was reported in clinical trials, and strongly predict reduced SVR across genotypes and clinically relevant patient subgroups. Whether and how week 4 viral load results should influence treatment decisions requires further study.

HCV-RNA quantification in liver bioptic samples and extrahepatic compartments, using the abbott RealTime HCV assay

Background & aimsWe evaluated the performance of a rapid method to quantify HCV-RNA in the hepatic and extrahepatic compartments, by using for the first time the Abbott RealTime HCV-assay. MethodsNon-tumoral (NT), tumoral (TT) liver samples, lymph nodes and ascitic fluid from patients undergoing orthotopic-liver-transplantation (N=18) or liver resection (N=4) were used for the HCV-RNA quantification; 5/22 patients were tested after or during direct acting antivirals (DAA) treatment. Total RNA and DNA quantification from tissue-biopsies allowed normalization of HCV-RNA concentrations in IU/μg of total RNA and IU/106 liver-cells, respectively. ResultsHCV-RNA was successfully quantified with high reliability in liver biopsies, lymph nodes and ascitic fluid samples. Among the 17 untreated patients, a positive and significant HCV-RNA correlation between serum and NT liver-samples was observed (Pearson: rho=0.544, p=0.024). Three DAA-treated patients were HCV-RNA “undetectable” in serum, but still “detectable” in all tested liver-tissues. Differently, only one DAA-treated patient, tested after sustained-virological-response, showed HCV-RNA “undetectability” in liver-tissue. ConclusionsHCV-RNA was successfully quantified with high reliability in liver bioptic samples and extrahepatic compartments, even when HCV-RNA was “undetectable” in serum. Abbott RealTime HCV-assay is a good diagnostic tool for HCV quantification in intra- and extra-hepatic compartments, whenever a bioptic sample is available

Analytical characteristics and comparative evaluation of Aptima HCV quant Dx assay with the Abbott RealTime HCV assay and Roche COBAS AmpliPrep/COBAS TaqMan HCV quantitative test v2.0

BackgroundThe Aptima HCV Quant Dx assay (Aptima assay) is a fully automated quantitative assay on the Panther® system. This assay is intended for confirmation of diagnosis and monitoring of HCV RNA in plasma and serum specimens. The purpose of the testing described in this paper was to evaluate the performance of the Aptima assay.MethodsThe analytical sensitivity, analytical specificity, precision, and linearity of the Aptima assay were assessed. The performance of the Aptima assay was compared to two commercially available HCV assays; the Abbott RealTime HCV assay (Abbott assay, Abbott Labs Illinois, USA) and the Roche COBAS Ampliprep/COBAS Taqman HCV Quantitative Test v2.0 (Roche Assay, Roche Molecular Systems, Pleasanton CA, USA). The 95% Lower Limit of Detection (LoD) of the assay was determined from dilutions of the 2nd HCV WHO International Standard (NIBSC 96/798 genotype 1) and HCV positive clinical specimens in HCV negative human plasma and serum. Probit analysis was performed to generate the 95% predicted detection limits. The Lower Limit of Quantitation (LLoQ) was established for each genotype by diluting clinical specimens and the 2nd HCV WHO International Standard (NIBSC 96/798 genotype 1) in HCV negative human plasma and serum. Specificity was determined using 200 fresh and 536 frozen HCV RNA negative clinical specimens including 370 plasma specimens and 366 serum specimens. Linearity for genotypes 1 to 6 was established by diluting armored RNA or HCV positive clinical specimens in HCV negative serum or plasma from 8.08 log IU/mL to below 1 log IU/mL. Precision was tested using a 10 member panel made by diluting HCV positive clinical specimens or spiking armored RNA into HCV negative plasma and serum. A method comparison was conducted against the Abbott assay using 1058 clinical specimens and against the Roche assay using 608 clinical specimens from HCV infected patients. In addition, agreement between the Roche assay and the Aptima assay using specimens with low HCV concentrations (</= 25 IU/mL by Roche) was tested using 107 clinical specimens.ResultsThe 95% LoD was 5.1 IU/mL or lower for serum and 4.8 IU/mL or lower for plasma depending on the HCV genotype. The LLoQ for the assay was 10 IU/mL. Specificity was 100% with 95% confidence intervals of 99.6 to 100% for serum and plasma data combined. The assay demonstrated good linearity across the range for all genotypes. The Precision as estimated by the standard deviation (sd) was 0.17 log or lower across the range of the assay for both serum and plasma. HCV viral load results were compared using the Aptima assay and the Abbott assay giving a slope of 1.06, an intercept of 0.08 and an R2 of 0.98. HCV viral load results were compared for the Aptima and Roche assays giving a slope of 1.05, an intercept of −0.12 and an R2 of 0.96. Positive and negative agreement for the Aptima assay vs the Roche assay was 89% for low level specimens.ConclusionThe Aptima assay is a highly sensitive and specific assay. The assay gave comparable HCV viral load results when compared to the Abbott and Roche assays. The performance of the Aptima assay makes it an excellent candidate for the detection and monitoring of HCV.

Comparison of three quantitative HCV RNA assays in samples from HCV genotype 1- or 4-infected patients treated with the NS3/4A protease inhibitor simeprevir

BackgroundMonitoring HCV RNA levels during treatment is an important tool for managing protease-inhibitor-based regimens, and different assays used in clinical practice can impact treatment decisions. ObjectivesThe concordance of three HCV RNA assays was determined, and their impact on treatment decisions assessed using samples from HCV genotype (GT) 1- and GT4-infected patients treated with the NS3/4A inhibitor simeprevir in combination with pegylated interferon-α/ribavirin. Study designPlasma samples collected during the simeprevir Phase III studies QUEST-1 and QUEST-2 (GT1), and RESTORE (GT4) were analyzed with the Roche High-Pure-System COBAS® TaqMan® HCV v2.0 (HPS), the Roche AmpliPrep COBAS® TaqMan® HCV v2.0 (CAP), and the Abbott RealTime HCV (ART) assay. ResultsIn GT1, of the 440 samples, 81% were undetectable (rapid virological response; RVR) by HPS at Week 4, 76% by CAP and 44% by ART. In GT4 (103 samples), RVR rates were 67% by HPS and 24% by ART. HCV RNA <25IU/mL at Week 4 was observed for 95–96% and 92% GT1 samples and 86% and 74% GT4 samples by HPS/CAP and ART, respectively. At Week 12, assay concordance for undetectability was high in GT1 and GT4, (95–98% and 93%, respectively). ConclusionsWhile different HCV RNA assays can lead to substantially different RVR rates, a good concordance was observed with a cut-off of 25IU/mL. Sustained virologic response rates among GT1 patients achieving RVR or <25IU/mL at Week 4 were high and similar between assays used. At later time points, when viremia is low, assay concordance was high.

Sequence Conservation of the Region Targeted by the Abbott RealTi m e HCV Viral Load Assay

The Abbott RealTime (RT) HCV assay targets the 5' untranslated region (UTR) of the HCV genome. Here, we analyzed the sequence variability of the assay target regions from 1,092 specimens. Thermodynamic modeling of the percentage of primers/probes bound at the assay annealing temperature was performed to assess the potential effect of sequence variability. An analysis of this large data set revealed that the primer and probe binding sites of the RealTime HCV viral load assay are highly conserved and that naturally occurring sequence polymorphisms are not expected to discernibly impact assay performance.

Performance Characteristics of the Cobas Ampliprep/Cobas Taqman V2.0 and the Abbott Realtime Hepatitis C Assays - Implications for Response-Guided Therapy in Genotype 1 Infections

With the advent of the protease inhibitors boceprevir and telaprevir a novel therapy approach for HCV genotype 1 infected subjects has become standard of care. Quantification of HCV viral load (VL) represents an important predictor of treatment response. Two different real-time PCR platforms, the COBAS Ampliprep/COBAS TaqMan v2.0 (CAP-CTM v2.0) and the Abbott RealTime (ART) HCV assay are most widely used. We performed a comparative evaluation of both systems focusing on genotype 1 HCV quantification using clinical specimens, the fourth WHO International Standard for HCV and the Paul Ehrlich National Standard, respectively. The HCV VL assays showed an excellent overall agreement in the clinical specimens studied (R(2)=0.912). Discrepant results were obtained at the low VL end. Four samples tested negative with CAP-CTM v2.0 but were detectable with ART and two samples were undetectable with ART but tested positive with CAP-CTM v2.0. The coefficient of variation in replicate measurements of both reference materials was higher for CAP-CTM v2.0 as compared with ART at the clinical decision point for boceprevir (≥100 IU/ml), but was similar for the two assays at the clinical decision point for telaprevir (≥1,000 IU/ml). The tendency for underestimation of the diluted standards was higher for ART than for CAP-CTM v2.0. Although both assays allowed accurate determination of VL levels in clinical samples, careful interpretation of results at the low VL end is essential. Furthermore, discontinuation of therapy based on single HCV RNA measurement should be carefully reconciled, unless the issue of assay variability has been addressed adequately.

Performance evaluation of the Artus hepatitis C virus QS-RGQ assay

Accurate determination of hepatitis C virus RNA level is essential for evaluating the response to antiviral therapy, to determine the duration of treatment, and to predict treatment outcome. Currently, two real-time based polymerase chain reaction assays are used widely to monitor the hepatitis C RNA level: the Abbott RealTime HCV assay and the Cobas Taqman HCV assay. Recently, a third assay has become commercially available: the Artus HCV QS-RGQ assay, which uses the QIAsymphony SP/AS platform for sample preparation and PCR-setup, and the Rotor-Gene Q for amplification and detection. In this study, the performance of the Artus HCV QS-RGQ assay was tested on 105 plasma samples and compared to that of the Cobas Taqman HCV assay. Linear regression analysis showed a good agreement between the two assays. A slightly better sensitivity was observed with the Cobas Taqman assay, while higher hepatitis C viral RNA levels were measured by the Artus HCV QS-RGQ assay in samples positive for hepatitis C genotypes 4. Taken together, the data suggest that the Artus HCV QS-RGQ assay is useful in a diagnostic setting. The combination with the versatile QIAsymphony SP/AS system may represent a major advantage for clinical virological laboratories aiming at optimizing their workflow.

Comparable performance of TMA and Real-Time PCR in detecting minimal residual hepatitis C viraemia at the end of antiviral therapy

Background Antiviral therapy for chronic hepatitis C may cause transient on-treatment response followed by post-treatment relapse. Objectives We have compared the prognostic value for post-treatment relapse of minimal hepatitis C residual viraemia detected at end-of-therapy by transcription mediated assay (TMA) and by Abbott RealTime PCR HCV assay. Study design Minimal residual viraemia was investigated in 202 HCV patients who had completed a full course of Pegylated Interferon (PEG-IFN) plus ribavirin and were HCV-RNA negative by conventional PCR in two separate serum samples obtained during the last week of therapy and the results were then correlated with post-treatment outcome. Results Minimal residual viraemia was detected in 22/202 (11%, 95% CI: 7–16%) and in 28/202 (13.8%, 95% CI 10–19%) patients by TMA and by Abbott RealTime HCV assay, respectively, with 92% concordant results. Post-treatment relapse was seen in 81.8% (95% CI: 60–93%) of TMA positive and in 82.1% (95% CI: 64–92%) of Abbott RealTime HCV assay positive cases compared to 16.6% (95% CI: 12–23%) of TMA negative and 17.2% (95% CI: 12–23%) of Abbott RealTime HCV assay negative patients. Conclusions These results indicate that TMA and the Abbott RealTime HCV assay have comparable sensitivity and specificity in identifying minimal residual viraemia at the end of antiviral therapy, with excellent predictive value for post-treatment relapse.